dpivsoft.Classes

class dpivsoft.Classes.Parameters

Bases: object

Container for all the parameter options used to perform PIV.

Default values are defined here. There are two ways to change the values for a specific DPIV run:

• Change the specific value manually on python shell or on the running script.

  Example: Parameters.box_size_1_x = 128

• Load all the parameters included in a yaml file by using readParameters classmethod.

  Example: Parameters.readParameters(‘folder/filename’)

box_size_1_x = 64

box_size_1_y = 64

no_boxes_1_x = 64

no_boxes_1_y = 32

window_1_x = 48

window_1_y = 48

box_size_2_x = 32

box_size_2_y = 32

no_boxes_2_x = 128

no_boxes_2_y = 64

window_2_x = 32

window_2_y = 32

no_iter_1 = 1

no_iter_2 = 2

direct_calc = False

mask = False

stereo = False

peak_ratio = 1

weighting = False

gaussian_size = 0

median_limit = 0.5

calibration = 1

delta_t = 1

class Data

Bases: object

Holds run-specific data such as the mask and its file paths.

path_mask = 'none'

path_stereo = 'none'

class Stereo_Calibration(npz_file)

Bases: object

Loads a stereo calibration from an .npz file: the pixel->world forward fits (fwd_*) and the Soloff world->pixel maps (map_*) for both cameras, plus the camera configuration.

load_variables(npz_file)

Read the calibration arrays from npz_file into attributes.

classmethod readParameters(fileName)

Load all PIV parameters from a yaml file and set them on the class (overwriting the defaults).

Parameters:

fileName (str) – Path to the yaml parameter file.

introParameters()

Introduce a parameter manually, not implemented yet (probably needed for a GUI)

class dpivsoft.Classes.grid

Bases: object

Holds the PIV grids (window centers and box origins) for both passes, built from the image size and the current Parameters.

classmethod generate_mesh(width, height)

Build the meshgrid of x and y positions of the correlation windows for the two passes, according to the selected PIV parameters, and store them as class attributes.

Parameters:

• width (int) – Image size in pixels.

• height (int) – Image size in pixels.

read_mesh(height, width)

Read the positions of a custom mesh from a file (not implemented yet)

class dpivsoft.Classes.Synt_Img

Bases: object

Contains the parameters to generate a pair of synthetic images following a given flow velocity field. The default values can be changed manually.

Variables:

• width (int) – Number of pixels in the x-direction of the generated image.

• height (int) – Number of pixels in the y-direction of the generated image.

• trazers_density (float) – Number of particles generated per pixel. Must be a float between 0 and 1.

• vel (float) –

  Characteristic velocity of the canonical flow used to generate the particle displacement.

  Note: it has a different definition for each flow.

• Shine_m (int) – Mean brightness of the tracer core (from 0 to 255).

• d_Shine (int) – Triangular variability of the tracer brightness.

• D_m (int or float) – Mean diameter of the tracers.

• d_D (int or float) – Triangular variability of the tracer diameter.

• noise_m (int) – Mean of the random noise.

• d_noise (int) – Triangular variability of the image noise.

• vel_profile (str) –

  Name of the flow velocity field used. The following options are available:

  Constant: Flow with a constant displacement of “vel” pixels on

  the x-direction

  Couette: Couette flow in x-direction using a moving condition

  of “vel” pixels between images on top wall. Bottom limit of the images is not moving.

  Poiseuille: Poiseuille flow in x direction with no-slip condition

  on top and bottom of the images. The parameter “vel” indicates the maximum velocity of the flow in pixels.

  Vortex: Flow generated by a Scully vortex (see Scully 1975). Vel

  is the maximum velocity of the vortex in pixel/frame.

  Frequency: Spatial frequency wave along the y-direction. This

  flow allows testing the PIV frequency response (see Scarano & Riethmuller, 2000). In this case the maximum pixel displacement on the wave is always 2 pixels, and the parameter “vel” indicates the wavelength.

• ext (str) – Extension used to save the images.

width = 1024

height = 1024

vel_profile = 'Vortex'

vel = 8

amp = 125.66370614359172

n_steps = 10

trazers_density = 0.05

Shine_m = 230

d_Shine = 80

D_m = 4

d_D = 3

noise_m = 1

d_noise = 1

ext = '.png'

class dpivsoft.Classes.GPU

Bases: object

Namespace for the GPU-side data. The OpenCL buffers and compiled kernels are attached as attributes at runtime by Cl_DPIV.compile_Kernels / initialization / processing.

gpu_data(thr)

Placeholder hook for attaching GPU data to the reikna Thread thr; the buffers/kernels are populated by Cl_DPIV instead.